This document discusses database management system (DBMS) languages and interfaces. It describes the main DBMS languages, including data definition language (DDL) used to define schemas, storage definition language (SDL) used to specify internal schemas, view definition language (VDL) used to specify views, and data manipulation language (DML) used to retrieve and update data. It also discusses different types of interfaces for interacting with a DBMS, such as menu-based, form-based, graphical, and natural language interfaces. The document provides examples of how each language and interface is used.

1. Database Systems
DBMS Languages and Interfaces Database Management Systems
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Lecture 5

2. Today’s agenda
• DBMS Languages
▫ Data Definition Language (DDL)
▫ Storage Definition Language (SDL)
▫ View Definition Language (VDL)
▫ Data Manipulation Language (DML)
• DBMS Interfaces
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3. DBMS Languages
• Data Definition Language (DDL): In many DBMSs
where no strict separation of levels is maintained, DDL is
used by the DBA and database designers to define both
conceptual and internal schemas.
• DBMS will have a DDL compiler whose function is to
process DDL statements in order to identify descriptions
of the schema constructs and store the schema
description in the DBMS catalog.
• Where a clear separation is maintained between the
conceptual and internal levels, the DDL is used to specify
the conceptual schema only.
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4. Storage Definition Language (SDL)
• Is used to specify the Internal schema
• The mapping between two schemas may be
specified in either DDL or SDL
• For the true three-schema architecture we need
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5. View Definition Language (VDL)
• Is used to specify the user view
• Mapping the view in conceptual schema
• In most DBMS DDL is used for both conceptual
and external schemas
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6. DBMS Languages
• Data Manipulation Language (DML): Used
to specify database retrievals and updates.
• DML commands (data sublanguage) can be
embedded in a general-purpose programming
language (host language), such as COBOL, C or
an Assembly Language.
• Alternatively, stand-alone DML commands can be
applied directly (query language).
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7. DBMS Languages
• High Level or Non-procedural Languages:
also called set at a time, e.g., SQL, are set-
oriented and specify what data to retrieve than
how to retrieve. Also called declarative
languages.
• Low Level or Procedural Languages: also
called record-at-a-time; they specify how to
retrieve data and include constructs such as
looping.
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8. DBMS Interfaces
• Menu-Based interfaces for Web Clients or
Browsing
• Form-Based Interfaces
• Graphical User Interfaces
• Natural Language Interfaces
• Interfaces for Parametric Users
• Interfaces for the DBA
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9. Menu-Based Interfaces for Web Clients
or Browsing
• List of options presented to the users called
menus that lead the user through the
formulation of a request
• No need to memorize the specific command or
syntax of a query language
• Query is composed step-by-step by picking
options from a menu that is displayed by the
system such as pull down menus.
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10. Form-Based Interfaces
• Displays a form to each user
• Fill the entries in the form (entering or
retrieving data)
• Designed for Naïve users
• Forms specification languages (SQL* forms,
Oracle Forms) help programmers to specify such
forms
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11. Graphical User Interfaces
• Displays a schema to user in diagrammatic form
• Specify the query by manipulating the diagram
• Utilizes both menus and forms
• Uses the pointing device
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12. Natural Language Interfaces
• Accepts request written in English
• Attempt to understand the request
• Has its own schema
• Include dictionary important words
• Produces the high-level query and submitted to
the DBMS
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13. Speech Input and Output
• Limited use of speech as an input query and
speech as an answer to a question or result of a
request is becoming commonplace.
• Applications with limited vocabulary such as
telephone directory, flight arrival/departure,
and bank account information are allowing
speech for input and output to enable ordinary
folks to access this information.
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14. Interfaces for Parametric Users
• Small steps of operations which have to perform
repeatedly i.e., Bank tellers
• Design some special interface
• Small set of abbreviated commands
• Proceed with a minimal number of keystrokes
(function keys)
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15. Interfaces for the DBA
• Most database systems contain privileged
commands that can be used only by the DBA's
staff.
• Creating accounts, granting authorizations
• Setting system parameters
• Changing schemas or access path
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